This invention relates generally to the microscopic examination of liquid specimens, and, more particularly, to an improved microscope slide having wells for holding a specimen during preparations prior to microscopic examination.
In serologic and other diagnostic procedures requiring the microscopic examination of liquid specimens, such as blood, urine, spinal fluid, sputum or cell cultures, the customary practice has been to place a small drop of the specimen to be analyzed in a well on a flat transparent microscope slide. Depending on the particular diagnostic procedure being performed, various substrates may be incorporated on the slide, prior to the addition of the drop, to initiate chemical reactions detectable in accordance with standard diagnostic procedures. Alternatively, substrates may be added to the drop after placing the drop on the glass plate. In either case, this reaction with the substrate frequently requires an incubation time of ten to thirty minutes or more, and the time liquid is in the well can be substantially increased by additional processing of the specimen in preparation for microscopic analysis. During this total time, the liquid specimen can spread throughout the entire well, and if an excess amount of specimen or substrate is present, or if the slide is accidentally bumped, the specimen liquid can spill outside the well. Since slides usually contain more than one well, this spillage can cause cross-contamination between the various liquid specimens and can adversely affect the accuracy of the subsequent microscopic examination.
Efforts have been made to obviate these problems of cross-contamination by providing deeper wells, but the experience with such wells has been less than completely satisfactory, primarily because the deep wells often induce focusing problems that hinder clear microscopic resolution. Also, providing wells much larger than required for the amount of liquid specimen present is inadvisable because some diagnostic procedures, e.g., staining, require a relatively even distribution of the liquid specimen throughout the entire well. Thus, there is a recognized need for a liquid specimen slide which will reduce the chances of cross-contamination in multiple-welled slides, yet not induce focusing or other problems. The present invention fulfills this need.